Sash balance



June 18, 1957 J DECKER ETAL 2,795,810

SASH BALANCE Filed Nov. 30, 1954 2 Sheets-Sheet 1 FIG. 2.

FIG.1.

FIGS.

INVENTORS lidnck U? Detlrer BY Mala/on H. Greg? June 18, 1957 F. J.DECKER ETAL 2,795,810

SASH BALANCE 2 Shets-Sheet 2 Filed Nov. 30, 1954 ATTO States 2,795,810SASH BALANCE Frederick J. Decker, Pittsford, and Mahlon H. Gregg,

Rochester, N. Y., assignors to The Caldwell Manufacturing C0., MonroeCounty, N. Y., a corporation of New York Application November 30, 1954,Serial No. 472,156 4 Claims. (Cl. 16-198) This invention relates tospring sash balances and is particularly directed to an adjustablebalance of this character, which is an improvement over previousbalances of cable is secured to the periphery of the drum and providedat its free end with a device for attachment to a sash. With the outerend of the cable held from entering the housing the spring is wound upand the axle set by a ratchet or some other form of locking device.

In some of the forms of prior devices of this character the tension ispermanently adjusted at the factory. In others there have been forms ofratchet adjustments provided whereby the axle may be rotated and resetrelative to the cable drum to increase or decrease the spring ten-SlOIl.

Spring sash balances in general are devices attachable to the frame ofdouble-hung window sash, one balance operating with a lower sash,movable upwardly to open position, and another balance operating with anupper sash movable downwardly to open position, each sash being slidablebetween suitable guides. The springs of such balances are wound ortensioned to a required extent when their respective sashes or windowmembers are in their normal closed position, the tension decreasing wheneither sash is moved to its closed position.

Spring sash balances which were formerly on the market were providedwith fiat metal tapes to carry the sash. Such types did not have therequired life, and in later years it has been common to use slendercables rather than tapes. The cables, however, had a tendency to pile upirregularly on the drivers or reels on which they were arranged to bewound, which sometimes resulted in shortened life of the cables.

One object of the present invention is to provide a construction inwhich the cables will lay themselves on the receiving reels or drums inclosely juxtaposed turns, making a closed helix, without requiringgrooves or guides cut into the peripheries of the drums.

Another object is to permit the use of inexpensive cast metal partsrequiring a minimum of machining, the plates being extremely simple toassemble and install.

Still another object of the present invention is to provide a nylon orslipbearing over which the cable is run from the drum to the attachmenton the sash, said bearing having a sufficiently large radii and hencesupplying a large enough bearing surface so that the cable moves oversaid bearing with a minimum of frictional resistance. In theconventional constructions of this type a cable roller is used, theroller of necessity being so small in diameter that the life of thecable is considerably shortened, due to the sharper angle of its. bendover the roller.

The construction of a preferred form of the invention, and its manner ofuse may best be understood by reference to the accompanying drawings, inwhich Fig. l is a top plan of a sash balance embodying the novelfeatures of the invention, the cover plate being removed;

atent Referring first to Figs. 1 and 2, the device as illustratedhas itsworking parts enclosed in a metal housing, designa-ted H in thedrawings, and approximately rectangular in form. This may be a casting,as indicated, or may be stamped from sheet material. In the drawing, thehousing has a flat bottom, or back plate 10, having an upwardlyextending rim 12. A cover plate or closure 14 is sized to fit within therim 12, and hollow bosses 16 preferably integral with. the bottom orback plate 10, extend through openings 18-. in the plate 12, the latterbeing positioned by shoulders 20 on the bosses 16. The plate 12 isretained on the bosses (after the inner members are in place), by.staking or upsetting the projecting, ends of'the bosses 16 againstsuitable chambered recesses around the openings 18 (Fig. 2).

It will be noted that the bosses 16, two of which are provided in eachunit, suitably spaced, are not normal to the general plane of thehousing bottom 10, i. e. not at a angle, but are disposed at an anglethereto which differs from a right angle by about 3 or 4 degrees. Thepurpose of this angular relation of the bosses 16 is to assure therequired closed-helix winding of the sash suspension cables asaforementioned, as the bosses 16 constitute fixed pintles or hubs onwhich the cable drums may rotate, as will be presently described.

It will be noted in Fig. 2 that each boss carries a cuplike drum,designated generally by the characters D and D, having a bottom 22 and acircular rim 24, the top of the drum being open. The bottom 10 of thehousing H, and the lower face of the cover plate 14 are recessed at 26and 28, respectively, to closely conform to the dimensions of the drumsto constitute alignment guides, so that the drums will not wobble on thesupporting bosses 16.

Each of the drums has an inturned lug 30 with which a hooked end 32 of aspiral fiat metal spring 34 engages. The inner endo-f each spring 34 ishooked at 38 into a slot 40 provided in each of the drum support bosses16. Obviously, when the drum D is turned counter-clockwise (as'viewed inFig. l) the tension or torque effect thereof will be increased, tendingto turn the drum D clockwise when and if it is permitted to unwind.Similarly, the spring 34 in drum D" tends to turn the latter in acounterclockwise direction (as viewed in Fig. 1) when it unwinds.

It should be understood that the winding of the springs occurs wheneither the upper or lower sash of a double hung window are moveddownwardly, and the unwinding occurs when either sash is moved upwardly,the springs therefore tending to support the sash by providing acountergravitational force. The springs, which are supplied with theunit, are selectedto nearly support the sash in a window in which thecomplete spring balance is installed.

The drum D. is provided with a cable or flexible wire C, and the drum D"is similarly provided with a cable C. One end of each cable enters aperforation in the rim of a drum. and is secured by a suitableclip 42..

From the drums, the cables D and C" extend to one end of the housing H,and then around a semicircular slip bearing, or guide 44, grooved at 36to suit the cables, that is set in a correspondingly shaped channel 46in the housing H. This guide is a preferred substitute for the pulleythat is usually included at this point in former structures, and isthought to be one of the novel features of the instant invention, bothfrom the consideration of more satisfactory operation and long service,and as a cheaper item of construction, requiring no maintenancewhatever. A preferred material for this guide is the well-known plasticmarketed under the trade name nylon. This material has been foundentirely satisfactory in normal use for the purpose above described,

It will be noted (Fig. 2) that the angular disposition of the bosses 16,in relation to the paths of the cables C and C" from the guides 44 tothe cable drums D and D" tends to keep the successive convolutions ofthe cables from piling up on one another as the drums revolve during thewindup of the cables, and therefore at all times the portions of thecables remaining on the drums are in close contact, one turn to thenext, and are as accurately disposed as they would be on a drum withgrooves so placed.

We have found that an angle of 93 has been satisfactory. However, thismay be increased within a range of depending upon the particular sizeand type of cable and the size of the drum employed. An angle of atleast 91 is necessary to give satisfactory operation.

Means are provided to permit either sash of a window to be renderedimmovable toward its open position. Adjacent portions of the housingthat surround the channels 46 are L-shaped pieces of metal 48 that areguided lugs 50 that project downwardly from the cover plate 14 to serveto hold these pieces 48 against the bottom of the housing H. Extensions52 and 54, beveled at their free ends, terminate at a point (Fig. 1)where they are almost, but not quite, caught between the straightportions and the helically-wound portions of the cables. Lugs 56extending on each piece 48 through the slots 58 in the housing. Theselugs therefore lie in recesses 60 and may be reached easily when thedevice is in its installed location (Fig. 7). A slight movement of oneor the other of these lugs toward the drums will cause the extensions 52or 54 to become wedged against the cables at W and will prevent theirrespective drums from rotating on the bosses 16 in the unwindingdirection.

The spring torque will draw metal pieces 48 and extensions 54 in underthe cable forcing it against the casing, thereby locking the rotation ofthe drum to the extent that the lower end of the cable may be detachedfrom the window sash and the sash removed, leaving the cable slack. Thewindow may thus be removed and reinserted without the cable snapping outof reach due to tension thereon. When the cable is again attached to thewindow and the window is moved downward, the drum reverses and the lockreleases to permit regular operation.

Referring now to Figs. 6, 7, and 8, it will be seen that theinstallation of the spring sash balance-one of which is installed ineach upper corner of a window framerequires the head or lintel member La frame to be recessed or cut through as at 62 to conform to the outlineof the housing H, so that a woodscrew 64, passing through a lug 66 onthe housing, may retain one end of the device in its required location.A lug 68 on the opposite end of housing H enters a recess that will. becut into the jam J of the frame, at the end of the head member L,Therefore only one actual fastening per unit is required.

The cable C and C from one unit may extend to a suitable securing studin either the upper sash S (a portion of which appears in Fig. 6), or tothe lower sash not shown.

Inasmuch as drum D will rotate counter-clockwise and drum D" will rotateclockwise when the cables are unwound, it is usually immaterial to whichsash either cable is afiixed, as in any case the springs 34 tend tosupport or balance the sash,

Having thus described a specific embodiment of the present invention asapplied to the construction of a particular sash balance, it is to beunderstood that this form has been illustrated more particularly fordisclosing the mode of operation and the principles involved than forlimiting the present invention to the specific structure that has beendisclosed, audit is to be understood that various modifications,adaptations and alterations can be applied to the specific form shown tobe met by the requirements of practice within the scope of the presentinvention, except as limited by the appended claims.

We claim:

1. A spring balance for window sash comprising a housing having parallelsides, a rotatable flat-surfaced drum mounted on a fixed axis at aninclined angle with respect to said housing, and a flat spiral springarranged Within said drum and having its ends connected respectively tosaid drum, and to said inclined fixed axis extending between the sidesof the housing upon which said drum rotates, whereby said rotatable drumis actuated, a cable, one end of which is attached to a window sash, andthe other end to said drum, said cable being fed onto said drum, saidfiat-surfaced drum being rotated on said fixed axis whereby said cableis wound on said drum.

2. A spring balance for window sash comprising a housing having parallelsides, a rotatable flat-surfaced drum mounted on a fixed axis at aninclined angle with respect to said housing, and a flat spiral springarranged within said drum and having its ends connected respectively tosaid drum, and to said inclined fixed axis extending between. the sidesof the housing upon which said drum rotates, whereby said rotatable drumis actuated, a cable, one end of which is attached to a window sash, andthe other end to said drum, said cable being fed onto said drum over aslip bearing, said flat-surfaced drum being rotated on said fixed axiswhereby said cable is wound on said drum.

3. A spring balance for window sash comprising a housing having parallelsides, a rotatable flat-surfaced drum mounted on a fixed axis at aninclined angle with respect to said housing, and a flat spiral springarranged within said drum and having its ends connected respectively tosaid drum, and to said inclined fixed axis extending between the sidesof the housing upon which said drum rotates, whereby said rotatable drumis actuated, a cable, one end of which is attached to a window sash, andthe other end to said drum, said cable being fed onto said drum at aninclined angle with respect to said fixed axis, said flat surfaced drumbeing rotated on said fixed axis whereby said cable is wound on saiddrum.

4. A spring balance for window sash comprising a housing having parallelsides, a rotatable fiat-surfaced drum mounted on a fixed axis at aninclined angle with respect to said housing, and a flat spiral springarranged within said drum andhaving itsends connected respectively tosaid drum, and to said inclined fixed axis extending between the sidesof the housingupon which said drum rotates, whereby said rotatable drumis actuated, a cable, one end of which is attached to a window sash, andthe other end to said drum, said cable being fed onto said drum, saidflat-surfaced drum being rotated on said fixed axis whereby said cableis wound on said drum in a closed-helix pattern.

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